This invention relates to a hard endoscope used as an auxiliary instrument when a surgical operation is carried out using a microscope.
Heretofore, when an operation is carried out with respect to a human brain, it is customary that a microscope C and an endoscope D are placed generally right above the head B (diseased part) of a patient A, as shown in FIG. 5. The endoscope D includes a body 1 and a hard insert portion 2 extending from the body 1. The insert portion 2 is provided on a distal end thereof with an objective lens and a plurality of relay lenses axially arranged side by side. The body 1 extends axially of the insert portion 2 and is provided on a rear end thereof with an ocular portion 3. An ocular lens is disposed in the ocular portion.
A camera E having a CCD (image sensor) is detachably attached to the ocular portion 3. A joint 4 projects from a distal end portion of the body 1. This joint 4 extends in a direction orthogonal to the axis of the body 1. A light guide cable 5 is connected to the joint 4. A bundle of optical fibers for transmission of illumination light reaches an illumination window formed on the distal end of the insert portion 2, through the light guide cable 5, the body 1 and the insert portion 2.
An intermediate portion of the body 1, i.e., the area of the body 1 between the ocular portion 3 and the joint 4, is firmly held by a chuck portion G at a distal end of a holding instrument F. By this, the endoscope D is supported in a predetermined position.
In the endoscope D having the above construction, the distal portion of the insert portion is inserted through a hole formed in the head B of the patient A, so that an image of the patient's brain, for example, side-view image, can be obtained. The image obtained by the endoscope D is photographed by the camera E and displayed in a monitor television in the form of a video image. The operator can carry out the operation while observing a magnified image of the brain obtained by the microscope C and further observing, where necessary, the side-view brain displayed in the monitor television.
However, since the insert portion 2 of the endoscope D thus constructed is inserted into the head B of the patient A in its generally vertical orientation, the body 1 and the camera E are brought into view field of the microscope C, thus disturbing the observation through the microscope C. If the body 1 should be brought out of the view field of the microscope C by declining the insert portion 2 in order for the body 1 not to disturb the operator's observation through the microscope C, a desired observation image could not be obtained, in some cases, by the endoscope D.
Another example of the endoscope used for assisting a micro-operation is disclosed in U.S. Pat. No. 5,601,549.